The Sun has expelled a third intense X-Class solar flare in 24 hours - but Nasa says not to worry.

It is "not physically capable of destroying Earth".

Our sun is currently nearing the period known as 'solar maximum', when activity on its surface rises to an 11 year peak. This solar cycle has been observed regularly since it was discovered in 1843, and indicates a regular fluctuation and not an anomaly.

"In an increasingly technological world, where almost everyone relies on cellphones, and GPS controls not just your in-car map system, but also airplane navigation and the extremely accurate clocks that govern financial transactions, space weather is a serious matter."

But the space agency added that while space weather is a problem, it is only in "the same way hurricanes are a problem". Nasa gives warnings to companies that might be affected by serious space weather so they can prepare ahead of time.

Meanwhile the UK government is examining the threat - though concern remains that current plans to proactively prevent damage to vital infrastructure such as the National Grid are not extensive enough to reduce the risk.